To characterize electrical impedance tomography (EIT) findings in patients with acute respiratory distress syndrome (ARDS) and to evaluate its clinical predictive value.

In this cross-sectional study, 92 patients with acute lung injury admitted to the intensive care unit (ICU) between December 2023 and December 2024 were enrolled. Participants were categorized into an ARDS group 53 cases, which included 32 patients receiving mechanical ventilation, and a non-ARDS control group 39 cases, which included 16 patients receiving mechanical ventilation. Data on clinical characteristics, the PaO₂/FiO₂ ratio, EIT-derived parameters of pulmonary ventilation and perfusion, EIT imaging features, and lower lung field CT scores were collected and analyzed to determine EIT characteristics and their predictive value.

Among mechanically ventilated ARDS patients, the application of positive end-expiratory pressure (PEEP) was associated with a significantly increased ventilation ratio in the non-dependent lung region (R2) (28.08±9.83)% and a decreased ventilation ratio in the dependent lung region (R3) (17.61±8.20) % compared to non-ventilated patients (P<0.01). The ventral (non-gravity-dependent) lung regions demonstrated a significantly higher overall ventilation ratio (64.27±13.52) % compared to the dorsal (gravity-dependent) regions (35.73±13.52) %(P=0.008). Concerning perfusion, ARDS patients showed a reduced perfusion distribution in R2 (25.93±4.72) % compared to non-ARDS patients (28.55±4.78) %. A marked right-left lung perfusion asymmetry was observed, with ARDS patients exhibiting a higher percentage of perfusion in the right lung (53.27±5.16) % versus non-ARDS patients (50.15±5.39) %(P=0.006). Lower lung CT scores demonstrated good predictive value for ARDS. EIT findings showed a high degree of concordance with corresponding CT images. Notably, EIT was capable of detecting significant regional ventilation or perfusion abnormalities, which served as indicators for underlying pathologies such as lobar consolidation, substantial pleural effusion, cardiomegaly, or pulmonary embolism.

Electrical impedance tomography is a valuable, non-invasive, radiation-free, and cost-effective bedside monitoring tool. It facilitates the early detection of aberrant pulmonary ventilation and perfusion distributions, potentially alerting clinicians to impending pulmonary complications and specific pathologies. Furthermore, EIT guidance can optimize clinical management strategies, including PEEP titration, potentially improving patient prognosis and reducing mortality.